2Department of General, Vascular and Transplant
Surgery, Medical University of Warsaw, Poland

Abstract

Although huge improvement has
been observed in endovascular repair of aneurysms involving visceral
arteries, in urgent cases open repair remained a method of choice. The
aim was to present a patient with symptomatic thoracoabdominal aortic
aneurysm measuring 11 cm in diameter (Crawford III). Due to concomitant
medication and morphology of aorta, there was neither possibility for
open repair, nor for standard stent-graft implantation. We decided to
apply Zenith t-Branch system, though visceral arteries anatomy haven’t
met morphological criteria from instruction for use (IFU) and previous
guidelines – patient had critically stenosed coeliac trunk, steep
left renal artery, blood to right kidney was supplied through the thick
thrombus and two extra kidney arteries to the lower pole were present. At
first, balloon was placed into the right renal artery to protect it from
embolization. Next, after Zenith Tx2 stent-graft deployment, t-Branch
system was implanted. Through branch dedicated to coeliac trunk, left
kidney artery was bridged using Advanta stents. Superior mesenteric artery
and right kidney artery were bridged by appropriate branches. All bridges
were reinforced by Zilver stents. Branch dedicated to left renal artery
was occluded using Amplatzer plug. Postoperative recovery and 4-month
follow-up was uneventful. In control computed tomography performed at
third month shrinking of the sac was observed to 96 mm and low-pressure
type II endoleak between coeliac trunk and additional left renal arteries
has been left for further observation. Application of Zenith t-Branch
is feasible and efficient method of treatment in urgent cases, even if
visceral arteries anatomy is outside IFU.

First case report of endovascular
juxtarenal aneurysm repair has been published in 1996 [1]. Since then,
for nearly two decades tremendous improvement has been observed in the
treatment of aneurysms involving visceral arteries [2, 3]. Fenestrated
and branched stent-grafts have nowadays established position and are
valuable alternative compared to open repair, which is demanding even
for the most experienced centres [4, 5]. On the beginning all branched
and fenestrated stent-grafts were custom-made (custom-made device,
CMD), and required up to 6–8 weeks for manufacture and delivery. The
time restriction precluded application endovascular method in case of
symptomatic or ruptured aneurysms. The need of solution in such cases
led to produce Zenith t-Branch device (Cook Medical, Bloomington, IN,
USA). Based on previous studies [6, 7] it was proven that more than half
of the patients meet criteria for endovascular repair of thoracoabdominal
aneurysms (multibranched endovascular aneurysm repair, mbEVAR) using
Zenith t-Branch. Recently, it has also received
CE approval.

The aim of the study was to present the
case of Zenith t-Branch application in endovascular treatment
of 11-cm thoracoabdominal aneurysm that hasn’t met morphological criteria specified in the manufacturer’s
instruction for use.

Case study

C.W., 71-year-old patient with abdominal
pain was admitted to surgical ward of the local hospital. In anamnesis,
patient had open surgery due to ruptured infrarenal aortic aneurysm 10
years ago, complicated by myocardial infarction two days after operation
and sigmoid necrosis with temporary colostomy formation five days after
surgery. In addition, patient suffered COPD and stable myocardial
angina. Diagnostic computed tomography (AngioCT) revealed eleven
centimetres TAAA – Crawford III, originating 25.9 cm distally to left
subclavian artery extending to the anastomosis of previously implanted
bifurcated vascular graft. There were no other causes of abdominal pain;
therefore patient was immediately transferred to our Department.

Because of previous extensive abdominal operations
and general co-morbidities, patient was disqualified from open repair of
TAAA. Moreover, preoperative AngioCT revealed critical stenosis in the
orifice of coeliac trunk (CT) (Fig. 1) and additional, two small arteries
to the inferior pole of left kidney (Fig. 2). Blood supply to the right
kidney had extra difficulty – blood was brought via 21 mm of thrombus
inside the aneurysm (Fig. 3). Additionally, the angle of the right renal
artery was very steep (Fig. 4). According to the instruction for use (IFU)
and guidelines from previous studies [6, 8], abovementioned conditions
excluded patient from Zenith t-Branch usage. But taking into consideration
high risk of the rupture, waiting for CMD was very hazardous option for
this patient. Therefore we decided to apply Zenith t-Branch beyond the
instruction for use. The device is a multi-branch stent-graft 32 mm in
upper and 18 mm in lower diameter. It has dedicated four branches for each
visceral artery in a specific distance and clock rotation. Outline of the
graft is presented in Figure 5. Relations of patient’s visceral arteries
anatomy are presented schematically in Figure 6 and in Table 1.

Afterwards, via left brachial artery, bridging
stents (Fluency Bard Peripheral Vascular, Tempe, USA reinforced with
bare self-expandable Zilver Cook stents) to SMA and right renal artery
were deployed from adequate branches. Main left renal artery was
cannulated via branch referred to coeliac trunk and bridged on two
balloon-expandable Advanta stents (Atrium Medical, USA) 6 × 38 mm
and 9 × 59 mm. Afterwards stents were reinforced by self-expandable
Zilver stent 6 × 80 mm. Branch referred to left renal artery (LRA)
was closed by Amplatzer Vascular Plug 4 (St. Jude Medical, USA) 4 × 8 mm. Additional renal arteries were not cannulated due to its small
diameter (1 mm each) and minor influence for kidney sufficiency. It has
not even appeared in aneurysm sacography before branch closure. Final
angiography showed proper contrast perfusion through stent-grafts and
branches and small, late leakage, probably through not yet thrombosed
Amplatzer (patient was on heparine
infusion with ACT raised to 250–300 sec). Blood flow to branches of
coeliac trunk was good, provided by expanded gastro-duodenal artery. Total
operation time was 290 minutes, radiation time 94.4 min, radiation dose
35.7 mgy/m2. Postoperative period was
not complicated with 1-day intensive care unit and 6-days in-hospital
stay. Four months follow-up was uneventful. Follow-up AngioCT at third
month revealed type II endoleak leak from surprisingly patent, extremely
compressed coeliac trunk and (or going into) one of additional renal
arteries. The Amplazer was thrombosed. Since maximum diameter reduced
to 96 mm, the leak was left for further observation.

Discussion

Endovascular repair, both of isolated
thoracic and infrarenal aortic aneurysms, are well-known, approved
methods of treatment [9–13]. In contrary, in case of TAAA open operation
was considered a “gold standard” despite the risk of morbidity and
mortality [14]. Recently, mbEVAR became valuable alternative to open
operation. Chuter et al. [15] as a first demonstrated that results
of mbEVAR are satisfactory with 9.1% perioperative mortality and
freedom-from-reintervention index 90.8% in one year follow-up.

Formerly, the main limitation in mbEVAR usage was
the time for manufacture and delivery of stent-graft due to variances
of visceral arteries anatomy. Gasper [6] and Bisdas [7] retrospectively
assessed preoperative AngioCT of elective patients who underwent mbEVAR
using CMD. Their relevant results showed that nearly two-thirds of
patients (66% and 63%, respectively) where suitable to apply t-Branch,
as the method of TAAA treatment.

IFU [8] requires, inter alia, suitable visceral
arteries anatomy:

– four indispensable arteries from the
abdominal viscera;

– all target arteries
to be accessible from an antegrade approach;

– CT and SMA to be 6 to 10 mm in diameter;

– renal arteries to be 4 to 8 mm in diameter;

– the distance between each cuff and the
corresponding arterial orifice is less than 50 mm;

–
projected onto the vessel wall deviates by no more than 45 degrees from
the long axis of the aorta.

Moreover, IFU makes a precaution
that t-Branch was not evaluated among patients with symptomatic and
ruptured TAAA. Our patient was not suitable to t-Branch due to most
above-mentioned points. He had symptomatic TAAA, with obstructed CT. What
is more, LRA couldn’t have been cannulated from the dedicated cuff,
because its level was too high and if the t-Branch would have been placed
higher, all other branches would be even more difficult to cannulate. In
addition, angle between stent deployed to right renal artery and long axis
of aorta was greater than 90 degrees. Unused cuff for left renal artery
was embolised by Amplatzer. The closure of the cuff is not mentioned
in the IFU, however described in the literature by the application of
“coils” [16].

Bisdas et al. [17] compared results of the
application CMD and t-Branch endograft in elective patients with
TAAA. Although perioperative success was complete in both groups,
mortality was higher in group treated with CMD (p = 0.04). What is more,
in six months observation none of the patient treated with t-Branch system
needed reintervention, while 10% of the other group needed secondary
procedure (p = 0.07). In the summary authors highlights indisputable
availability of the t-Branch system and good short-term outcomes.

Another essential issue to discuss in this case
report is surveillance after open repair of abdominal aortic aneurysm
(AAA). Presented patient haven’t had any ultrasound examination
to assess aortic diameter above anastomosis for 10 years. Fontaine et
al. [18], observed aneurysm formation proximally to the prosthesis in 32%
of patients 10.3 years after AAA repair. Biancari et al. [19] found that
in 15 year follow-up 12.5% of study group had any new aortic aneurysm
and nearly 3% of all had TAAA. Thus, after open operation of AAA all
patients must be under surveillance with at least periodic ultrasound
examination.

“Chimney” technique, and its further
modification – “periscope”, are alternatives in urgent symptomatic
and ruptured TAAA. In presented case we did not decide to use it due to
longitudinal size of the aneurysm [14]. Moreover, multicentre study of
Lachat et al. [21] showed that 25% of patients who had above-mentioned
techniques, at the time of discharge had endoleaks type I and III. Though
during follow-up most of the leaks thrombosed spontaneously, it was
considerable risk of postoperative rupture of 11-cm aneurysm in early
period. On the other hand, chimney technique is known as safer in case
of substantial thickness of intramural thrombus [22]. Manoeuvres before
and during deployment during mbEVAR may cause embolization of target
vessels. That was the reason of balloon placement in RRA before t-Branch
deployment.

Conclusion

We can conclude that in urgent situation
the application of Zenith t-Branch stent-graft outside the anatomical
requirements is feasible and could be good treatment option for
TAAA.

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